Since being signed into law two years ago the Patient Protection and Affordable Care Act, referred to as ‘Obamacare’ by its critics, has polarised American society.

Despite representing the largest expansion of social safety in four decades, extending healthcare to 32 million Americans, preventing insurance companies from denying coverage because of pre-existing medical conditions and limiting how much older people can be charged, 26 states have challenged its legality at the country’s highest court.

The nine justices are being asked to rule on whether the law’s requirement that every American pay for healthcare insurance is in violation with the US constitution.

The first of three days of hearings centred on whether the court was even allowed to rule on the reform, owing to an obscure piece of 19th century legislation saying laws cannot be reviewed in terms of tax until the tax in question has been collected; the penalty for those that refuse to pay for insurance is not due to kick in until 2015.

The healthcare reform has attracted fierce criticism in some sections of US society (Picture: Reuters)

The four remaining candidates for the Republican party’s nomination to challenge Mr Obama in this November’s general election have all pledged to repeal the healthcare reform if elected.

With the justices expected to rule on the case by June, the result could have a massive impact upon the election result.

Four justices with liberal leanings appointed by Democratic presidents – two from Mr Obama – sit in the court with five conservative justices appointed by Republicans, meaning one conservative justice has to side with the liberals in order for the healthcare reform to remain law.

Due to the intense interest in the case audio recordings of the arguments made before the justices will be released on the same day they take place.